| While Woundweavr's wu is correct and that is indeed the first gun that was called the Colt 45, nowadays that name is used to mean the m1911 Government Model pistol.
The 1911 is the epitome of a legendary weapon, the Discovery Channel program Decisive Weapons even used it as an example of the weapon that defined a people, the 1911 was to Americans what the samurai sword was to the Japanese.
Though legends and stories abound about the 1911, it really wasn't that decisive a weapon, infantry won the ground war with the M1 Garand but indeed, they had the trusty 1911 with them all the way.
The revolver Colt 45 fired the .45 Colt or what some call the .45 Long Colt, the m1911 fired the .45 ACP round.
In popular western lore, the .44 is king. | 
